Old wives tale, not too scientific, but something an impressionable 9th grader took to heart in the advance of Donna in 1960 was the appearance of "mares tales" in the otherwise clear sky approaching at 40k feet from the southeast. My science teacher, a navy vet who worked in the weather service in the Philipines, called us all out to see them and then said he had seen these numerous times as cyclones approached and invariably they announced the arrival of a tropical system. He correctly predicted we would be significantly influenced by that sysstem which was still down near Puerto Rico..
This morning as I drove down at dawn from Manatee County to Lee County...there they were ...this is a large system and, although weak at the moment, will command a lot of geography. Based on this unscientific observation, I feel confident that in about 72 to 96 hours, southwest and west central Florida will experience whatever this system has to offer...we'll see,,,